1. Field of the Invention
The present invention relates generally to fluid handling equipment and, more particularly, to a lavatory faucet having a manually-actuated push button control valve apparatus.
2. Discussion of the Prior Art
It is conventional to provide lavatories with manual push button hot and cold water controls. For example, in prison cells, a lavatory is provided which includes a wash bowl or basin and a splash guard fixture that is secured to the wall of the cell over one or more circular holes in the wall through which plumbing extends to the lavatory.
A typical prison lavatory includes mechanical valve assemblies in the hot and cold water plumbing for controlling the flow of water to a tap of the lavatory. Each valve assembly includes a valve movable between flow-blocking and flow-permitting positions, a spring for biasing the valve toward the flow-blocking position, and a mechanical valve opening mechanism for opening the valve against the force of the spring when a physical pressure is applied to one of push buttons. A delay mechanism is also provided in the valve assembly for keeping the water running for a predetermined time before the spring is allowed to move the valve back to the flow-blocking position.
The conventional lavatory also includes an actuator assembly for transmitting movement of the push buttons to the opening mechanism of the valve assembly. The actuator assembly includes a linkage having a first end received in one of the push buttons, and a second end connected to the opening mechanism of the valve assembly. The position on the linkage at which it is connected to the opening mechanism is adjustable to permit the apparatus to be installed in lavatories of varying dimensions.
Several problems arise with the use of such conventional valve apparatuses. For example, mechanical valve assembly has a much shorter useful life than is desirable for a device to be put in such a harsh environment as a prison cell where lavatories are subjected to heavy use and abuse. As a result, the valve apparatuses of known construction must be replaced frequently at a significant expense.
Another known type of valve apparatus includes a pneumatically actuated valve assembly, and an actuator assembly for supplying pneumatic pressure to the assembly. The actuator assembly includes a diaphragm housing, and an elongated rod extending into the housing for moving the diaphragm to create a pressure differential at the valve assembly.
Several problems arise from the use of a pneumatic lavatory of this type. For example, in the construction of prison cell lavatories, the size of the hole through the wall for the plumbing of the lavatory is made as small as possible, typically about four inches in diameter, to deter escape of prisoners. Thus, all of the plumbing for the lavatory, including the actuator assemblies for the hot and cold water, must fit within the hole while allowing access to the plumbing for installation and repair. The known pneumatic actuator is not suitable for such uses because the diaphragm housing and diaphragm present a diameter greater than two inches. Because the actuator assemblies for the hot and cold water are typically located near the top of the splash guard fixture above the basin, these assemblies are disposed adjacent the upper circumferential edge of the wall opening, and very little clearance is available to accommodate such large diameter actuators.